Many functions of modern devices in automotive, consumer and industrial applications, such as converting electrical energy and driving an electric motor or an electric machine, rely on power semiconductor devices. For example, Insulated Gate Bipolar Transistors (IGBTs), Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and diodes, to name a few, have been used for various applications including, but not limited to switches in power supplies and power converters.
A power semiconductor device usually comprises a semiconductor structure configured to conduct a load current along a load current path between two load terminal structures of the device. Further, the load current path may be controlled by means of a control electrode, sometimes referred to as gate electrode. For example, upon receiving a corresponding control signal from, e.g., a driver unit, the control electrode may set the power semiconductor device in one of a conducting state and a blocking state.
In the driver stage of an inverter, there is typically a direct current (DC) capacitor that is charged from an alternating current (AC) input. As an example, to drive three-phase motors from a single-phase input, it is typical to use an input bridge rectifier, a DC capacitor, and voltage source inverter (VSI). The input bridge rectifier charges the DC capacitor from the single phase AC input. During steady state operation, the DC capacitor in front of the VSI provides a nearly constant DC voltage which is transferred by the VSI to the voltage and current levels required to operate the motor.
However, during power-up of the application, the DC capacitor has to be charged completely starting at zero charge or at a low-level of charge up to the steady state level. Depending on the size of DC capacitor, the charging may result in a very high inrush current causing a huge stress on the input bridge rectifier and the DC capacitor.
Therefore, an improved device capable of limiting inrush current may be desirable.